By JOHN PYE and KEIRAN SMITH, AP Sports Writers

MELBOURNE, Australia — Jessica Pegula knocked podcast pal and defending champion Madison Keys out of the Australian Open on Monday (Sunday night PT) and moved into a quarterfinal against Amanda Anisimova, another all-American match.

Their fourth-round wins on Day 9 meant four Americans reached the women’s singles quarterfinals in Australia for the first time since 2001, when Serena and Venus Williams, Jennifer Capriati, Monica Seles and Lindsay Davenport made it to the last eight.

“Sucks that one American has to go out in the quarterfinals,” Anisimova said.

Pegula had a slightly different view: “At least one of us will get through, and I think that’s great for American tennis. It’s been pretty crazy how well the women have been doing and how many top-ranked girls there are. I’m just happy to be a part of that conversation.”

Pegula and Anisimova advanced a day after No. 3 seed Coco Gauff and 18-year-old Iva Jovic earned their places on the other side of the draw.

Pegula’s 6-3, 6-4 win at Rod Laver Arena ended Keys’ first Grand Slam title defense in a tough section of the draw.

Anisimova, runner-up at the last two majors in Wimbledon and the U.S. Open, advanced 7-6 (4), 6-4 over Wang Xinyu as the temperature started rising at Melbourne Park, and organizers triggered the heat stress policy which allowed for extra cooling breaks.

Pegula is into the quarterfinals for the fourth time in Australia but has never previously gone beyond that round at the season-opening major.

“I have been seeing, hitting, moving, I feel like very well this whole tournament, and to be able to keep that up against such a great player as Maddie and defending champion was going to be a lot tougher of a task today,” Pegula said. “I was still able to do that really well.”

Pegula and Keys had played three times previously, and Keys had won the last two. But on Monday it was Pegula who dominated, racing to 4-1 leads in both sets.

“I felt like if I didn’t hit a really good ball immediately, she was in charge of the points,” Keys said. “I was kind of struggling to kind of get that dominance back.”

Pegula’s best performance in a major was making the U.S. Open final in 2024, where she lost to Aryna Sabalenka. The top-ranked Sabalenka is aiming for a third Aussie title in four years.

Six-time major champion Iga Swiatek ended the fairytale run of qualifier Maddison Inglis to set up a quarterfinal with fifth-seeded Elena Rybakina.

The second-seeded Swiatek, who is chasing her first Melbourne title and a career Grand Slam, routed the Australian, 6-0, 6-3, at Rod Laver Arena. Inglis advanced to face Swiatek when Naomi Osaka withdrew from their third-round match with an injury.

Rybakina, the runner-up to Sabalenka here in 2023, advanced over Elise Mertens, 6-1, 6-3.

Anisimova was getting frustrated toward the end of the second set, hitting herself with her racket when she missed a service return. She also damaged a shoe.

Just as the No. 4 seed was about to serve for the match, the tournament’s heat stress index scale hit 4, which means extra cooling breaks are allowed after the second set in women’s singles and third set in men’s singles matches.

It didn’t become a factor, with Anisimova closing with an ace to reach the Australian Open quarterfinals for the first time.

“What a battle out there. Tough conditions against a really good opponent,” she said. “There were a lot of fans from China today but, honestly, it made the atmosphere great.”

SINNER ACES BOUNCE-BACK TEST

Jannik Sinner might have felt lucky to survive his third-round match, but he rebounded quickly in a straight-sets win over fellow Italian Luciano Darderi to reach the quarterfinals for a ninth consecutive Grand Slam event.

The two-time defending champion struggled with the extreme heat and cramping in his Saturday afternoon win over No. 85-ranked Eliot Spizzirri, and only took control after the roof was closed in the third set.

Sinner later admitted he got a bit lucky with the timing of the extreme heat policy being invoked, leading to an 8-minute break to close the roof. He was also able to refresh in a 10-minute extra cooling break between the third and fourth sets.

In an evening match in cooler conditions, he was cruising until Darderi lifted his tempo in the third set. Second-ranked Sinner missed match points in the 10th game on his opponent’s serve but then clinched victory, 6-1, 6-3, 7-6 (7-2).

Darderi, who saved two match points on his serve, took the first two points of the tiebreaker but then had to pause for a few moments before serving because of a baby crying in the crowd at Margaret Court Arena.

He didn’t win another point, with Sinner reeling off the next seven to triumph in 2 hours, 9 minutes.

It extended his unbeaten streak to 18 against other Italians on tour and earned a quarterfinal against No. 8 Ben Shelton or No. 12 Casper Ruud, who were playing the late match.

“It was very, very difficult. We’re good friends off the court,” Sinner said. “Third set I had some break chances, I couldn’t use them. I got tight, so very happy I closed it in three sets.”

Sinner had 19 aces – a personal record – and no double-faults and said he was satisfied with the work he put into his serve over the offseason.

He also wanted to emphasize some minor changes to his game, including going to the net and trying to mix up his game.

In a tough hold in the third set, Sinner saved a breakpoint by changing the direction of the rally with a forehand drop shot, bending his knees low to win the point. He serve-and-volleyed to hold that game.

“Still room to improve, but very happy with how I’ve come back,” he said. “Now for sure, it (the serve) is a bit more stable. I try to go more to the net and being more unpredictable.”

MUSETTI TOPS AILING FRITZ

Lorenzo Musetti reached the quarterfinals for the first time in Australia with a 6-2, 7-5, 6-4 win over ailing American Taylor Fritz.

It completed a Grand Slam set of quarterfinals for the 23-year-old Italian.

The fifth-seeded Musetti has had a disrupted run, with members of his support team having to return home for personal reasons. He also had to leave his family behind after the birth in November of his second son.

“I feel more mature on the court. I’m playing better for that, and for them,” he said.

His next mission is against a rested Novak Djokovic. The 24-time major winner had been scheduled to be the featured night match at Rod Laver Arena on Monday but had a walkover into the quarterfinals after his opponent Jakub Mensik withdrew from their scheduled fourth-round match with an abdominal injury.

While Monday’s win marked a milestone for Musetti, for the ninth-seeded Fritz, the fourth-round match signaled that his body might have reached its limit.

The 2024 U.S. Open runner-up revealed in a post-match news conference that he had arrived in Melbourne in two minds about his fitness, and had nearly withdrawn because of knee and abdominal issues.

“I was fully ready to shut it down for a couple of months to get it better,” Fritz said, adding that he had told his team: “If it stays how it is, we are just going to have to stop. I can’t play through this.”

His physiotherapist had different ideas.

“My physio, who is great and I trust him, he said that he thinks there’s a pretty solid chance that we can do all the rehab protocol and do everything we need to do while I’m still playing,” Fritz said.

After feeling discomfort in his third-round victory over 40-year-old Stan Wawrinka, a much sterner test against Musetti proved too much.

Despite feeling “very good” in his warmup, albeit with his torso heavily strapped to help his obliques, Fritz said painkillers failed to bridge the gap.

“I thought they would maybe kick in. It didn’t do anything,” he said. “A lot of my mistakes came from me pulling up, not feeling like I’m loading my knee hard enough.”

Retiring from the match wasn’t really a consideration.

“Most of the time when I’m playing through an injury, I can just go on the court and just not think about it and just, like, play and get into the match,” Fritz said. “I just could not today.

“I’m not the kind of person that pulls out. Especially in the second set, I was just really hoping I could get something going.”

The 28-year-old Fritz said he’s hoping he can play the tournament in Dallas but will have to wait and see how his body recovers.

“I don’t know why my knee got so much worse kind of in the last three days,” he said. “It was feeling really good through my first two rounds and all the practices before that.

“I don’t know if it’s just the overload of playing physical three, four sets, stuff like that. But you know, I have some more time to heal it. I feel like (if) I keep up with the rehab, it’s going to keep getting better.”